1. Field of the Invention
The present invention relates to a medical image processor for, and a medical image processing method of, processing a medical image.
2. Description of the Related Art
A medical image diagnosis system includes: a medical imaging apparatus configured to take a medical image; and a medical image processor configured to process the medical image. Examples of the medical imaging apparatus are an X-ray tomograph (an X-ray CT apparatus) and the like. This X-ray tomograph is an apparatus configured to: irradiate a subject with X-rays; detect the X-rays transmitted through the subject; and display an inside (a target body part) of the subject as a CT images.
In diagnoses of the coronary arteries using the above medical image diagnosis system, a physician manually classifies the coronary arteries into four areas: calcification, a lumen (a contrast medium), an external wall and a plaque. A clustering algorithm has been developed to perform this classification automatically (see JP-A No. 2003-79606 (KOKAI), for instance). In this conventional algorithm, two-dimensional slice angiographic images are used to automatically calculate the threshold values and thereby perform classification.
In the above-mentioned two-dimensional process, however, a classified area such as a plaque area or a calcification area suddenly appears in, or disappears from, some of a series of adjacent slice images. Accordingly, the continuity of the classified area in a slice direction (an extending direction of the blood vessel) is interrupted. In addition, overall blurring of calcification is detected as a lumen. For this reason, a false detection of a lumen due to blurring of the calcification occurs.